The paper studies the mechanics function and break the mechanism of the soft soil foundation,puts forward construction method of the soft soil quality pipe groove dig,key introduces the construction technigue of steel pile shield in deep dig,points out finally that the engineering deal of open dig the groove is big specific weight in the piping under construction,should cause to value.

According to the experimental study of the quick backfilling of the modified slag soil from the groove excavation in 2006 Nanjing City Xiangtanshan Water Supply Project and 2007 Mufu Road (W) D1000 Water Supply Pipeline Reconstruction Project, the article finds out the strength standard of the backfilling material suitable for the groove excavation of the urban roads.